1. Field of the Invention
The present invention relates to a microwave reactor and a method of producing a polymer compound using the reactor.
2. Description of the Related Art
It has been reported that microwave irradiation to a chemical reaction system, such as a synthesis reaction, a decomposition reaction, or an oxidation-reduction reaction, accelerates the chemical reaction and enhances the reaction rate. At present, these chemical reactions under microwave irradiation are positioned in the technical field of microwave chemical process and have been diligently studied.
In general, there is a correlation between the power of microwave radiation and the chemical reaction-accelerating effect, and it is possible to further enhance the reaction rate by increasing the power of microwave radiation. However, irradiation with high-power microwaves may induce excessive heating of the chemical reaction system to make the control of the chemical reaction difficult. Thus, the irradiation is disadvantageous from the viewpoint of chemical reaction control. As a method of solving these problems, U.S. Pat. No. 5,932,075 discloses a microwave reactor equipped with a cooler.
However, according to investigation of the present inventor, in a chemical reaction using a microwave reactor equipped with a cooler like that disclosed in U.S. Pat. No. 5,932,075, the chemical reaction-accelerating effect by high-power microwave irradiation was not observed in some cases. As the reason of this, the present inventor conjectures that a low-temperature region, the temperature of which has been rapidly decreased, is generated in the vicinity of the cooler and that a chemical reaction-inhibiting effect caused by this low-temperature region competes with the chemical reaction-accelerating effect of the microwave irradiation.
The low-temperature region herein indicates the region that is generated in the vicinity of a cooler placed inside a reaction solution and the temperature of which has been rapidly cooled. It is thought that in the low-temperature region, there is further a cool-temperature region in which the reaction rate is one half or less of the reaction rate in the heated reaction solution.
If the cooling by the cooler is stopped in order to inhibit the occurrence of the low-temperature region, the temperature of the reaction solution increases to the boiling point thereof or more, and thereby the chemical reaction does not proceed as expected.